C語言實現堆排序代碼

void heapsort(int arr[], unsigned int N) 
{ 
    unsigned int n = N, i = n/2, parent, child; 
    int t;


for (;;) { /* Loops until arr is sorted */ 
    if (i > 0) { /* First stage - Sorting the heap */ 
        i--;           /* Save its index to i */ 
        t = arr[i];    /* Save parent value to t */ 
    } else {     /* Second stage - Extracting elements in-place */ 
        n--;           /* Make the new heap smaller */ 
        if (n == 0) return; /* When the heap is empty, we are done */ 
        t = arr[n];    /* Save last value (it will be overwritten) */ 
        arr[n] = arr[0]; /* Save largest value at the end of arr */ 
    } 

    parent = i; /* We will start pushing down t from parent */ 
    child = i*2 + 1; /* parent's left child */ 

    /* Sift operation - pushing the value of t down the heap */ 
    while (child < n) { 
        if (child + 1 < n  &&  arr[child + 1] > arr[child]) { 
            child++; /* Choose the largest child */ 
        } 
        if (arr[child] > t) { /* If any child is bigger than the parent */ 
            arr[parent] = arr[child]; /* Move the largest child up */ 
            parent = child; /* Move parent pointer to this child */ 
            //child = parent*2-1; /* Find the next child */ 
            child = parent*2+1; /* the previous line is wrong*/ 
        } else { 
            break; /* t's place is found */ 
        } 
    } 
    arr[parent] = t; /* We save t in the heap */ 
} 

} </pre>